The present invention generally relates to an optical device and a manufacturing method thereof. More particularly, the present invention relates to an optical device used in, for example, a digital camera and a manufacturing method thereof.
Optical devices having a plurality of optical elements formed in a substrate and a plurality of lenses corresponding to the optical elements have been used in digital cameras and the like. In such optical devices, contamination of lenses is a critical problem since light enters an optical device through the lenses. A transparent member that covers the lenses is therefore provided to prevent contamination of the lenses. The top surface of the transparent member serves also as a reference plane for mounting the optical device.
In general, the plurality of lenses are covered by a protective layer having a low refractive index, and the transparent member is fixed onto the protective layer with an adhesive interposed therebetween (for example, see Japanese Patent Laid-Open Publication No. 2003-31782). With this structure, the transparent member can be easily fixed because the protective layer forms a flat surface over the lenses.